// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "device_orientation_event_pump.h"

#include <string.h>

#include <cmath>

#include "content/public/renderer/render_thread.h"
#include "third_party/WebKit/public/platform/modules/device_orientation/WebDeviceOrientationListener.h"

namespace content {

const double DeviceOrientationEventPumpBase::kOrientationThreshold = 0.1;

DeviceOrientationEventPumpBase::DeviceOrientationEventPumpBase(
    RenderThread* thread)
    : DeviceSensorEventPump<blink::WebDeviceOrientationListener>(thread)
{
}

DeviceOrientationEventPumpBase::~DeviceOrientationEventPumpBase() { }

void DeviceOrientationEventPumpBase::FireEvent()
{
    DCHECK(listener());
    blink::WebDeviceOrientationData data;
    if (reader_->GetLatestData(&data) && ShouldFireEvent(data)) {
        memcpy(&data_, &data, sizeof(data));
        listener()->didChangeDeviceOrientation(data);
    }
}

static bool IsSignificantlyDifferent(bool hasAngle1, double angle1,
    bool hasAngle2, double angle2)
{
    if (hasAngle1 != hasAngle2)
        return true;
    return (hasAngle1 && std::fabs(angle1 - angle2) >= DeviceOrientationEventPumpBase::kOrientationThreshold);
}

bool DeviceOrientationEventPumpBase::ShouldFireEvent(
    const blink::WebDeviceOrientationData& data) const
{
    if (!data.allAvailableSensorsAreActive)
        return false;

    if (!data.hasAlpha && !data.hasBeta && !data.hasGamma) {
        // no data can be provided, this is an all-null event.
        return true;
    }

    return IsSignificantlyDifferent(
               data_.hasAlpha, data_.alpha, data.hasAlpha, data.alpha)
        || IsSignificantlyDifferent(
            data_.hasBeta, data_.beta, data.hasBeta, data.beta)
        || IsSignificantlyDifferent(
            data_.hasGamma, data_.gamma, data.hasGamma, data.gamma);
}

bool DeviceOrientationEventPumpBase::InitializeReader(
    base::SharedMemoryHandle handle)
{
    memset(&data_, 0, sizeof(data_));
    if (!reader_)
        reader_.reset(new DeviceOrientationSharedMemoryReader());
    return reader_->Initialize(handle);
}

void DeviceOrientationEventPumpBase::SendFakeDataForTesting(void* fake_data)
{
    blink::WebDeviceOrientationData data = *static_cast<blink::WebDeviceOrientationData*>(fake_data);

    listener()->didChangeDeviceOrientation(data);
}

} // namespace content
